president george w. bush over campaign finance, climate change and torture. >> first of all torture doesn't work as we proved. >> now with trump mccain's differences may be even more profound. over issues like immigration and especially national security. >> i am in disagreement with many of the national security positions that donald trump has taken. >> reporter: last year trump ridiculed mccain for being captured by the north vietnamese during the vietnam war. >> he's a war hero because he was captured. i like people that were about captured, okay? i hate too tell you -- >> there is a body of heros that i'd like to see him retract that statement. not about me but about the others. >> but trump not backing down. >> i don't like the job yom is doing in the senate because he's not taking care of the veterans.